Most of the naturally occurring radioisotopes have relatively long half-lives. They are also among the elements that are not well processed by the human body. Therefore, medical applications usually require the use of radioisotopes that are artificially produced.
We have dealt with the topic of radioactivity in earlier chapters of this wikibook and then moved on to discussing the interaction of radiation with matter, radiation detectors and imaging systems. We return to sources of radioactivity in this chapter to learn about methods used to produce radioisotopes.
The type of radioisotope valuable for nuclear medicine imaging should have properties that minimize the radiation dose to the patient. Because of this, they typically have a short half-life and only emit gamma rays—no alpha or beta particle emissions. From an energetic point of view, the gamma ray energy should not be so low that the radiation is completely absorbed before exiting the patient's body and not so high that it is difficult to detect. For this reason, most of the radioisotopes used emit medium-energy gamma rays, i.e. between about 100 and 200 keV. Finally, since the radioisotope must be incorporated into some form of radiopharmaceutical, it should also be capable of being manufactured in a form amenable to chemical, pharmaceutical, and sterile processing.
The production methods we will consider are nuclear fission, atomic bombing and the radioisotope generator.
Contents
- 1 nuclear fission
- 2 Nuclear Bombing
- 3 Radioisotopengenerator
- 4 Operation of a 99m Tc generator
- 5 Externe Links
nuclear fission[edit|edit source]
We were introduced to spontaneous nuclear fissionChapter 2where we saw that a heavy core can break into multiple fragments. This decay process can be induced when certain heavy nuclei absorb neutrons. After absorbing a neutron, such nuclei break up into smaller fragments with atomic numbers between about 30 and 65. Some of these new nuclei are of value in nuclear medicine and can be separated from other fission fragments by chemical processes.
The splitting process is controlled in a device called aNuclear reactor. Such a reactor exists in AustraliaLucas Heights in New South Walesand there are many others around the world.
Nuclear Bombing[edit|edit source]
In this method of producing radioisotopes, charged particles are accelerated to very high energies and caused to collide with a target material. Examples of such charged particles are protons, alpha particles and deuterons. When these particles collide with nuclei in the target material, new nuclei can be formed. Some of these cores are of value to nuclear medicine.
An example of this process is the production of22Well where a goal from24Mg is bombarded with deuterons, that is:24mg+2H→22Already+4Is.
A deuteron you will rememberChapter 1is the second most abundant isotope of hydrogen2H. When it collides with a24Mg-Kern a22An Na nucleus plus an alpha particle is formed. The target is exposed to the deuterons for a period of time and then chemically processed to separate them22At the core.
The type of equipment commonly used for this method of radioisotope production is called aCyclotron. It consists of an ion gun to generate the charged particles, electrodes to accelerate them to high energies, and a magnet to direct them towards the target material. All arranged in a circular structure.
Radioisotope-Generator[edit|edit source]
TheMethodis often used to produce certain short-lived radioisotopes in a hospital or clinic. It involves obtaining a relatively long-lived radioisotope that decays into the short-lived isotope of interest.
A good example is99mAs already mentioned, Tc is the most widely used radioisotope in nuclear medicine today. This isotope has a half-life of six hours, which is pretty short if we're going to have it delivered directly from a nuclear facility. Instead, the nuclear facility supplies the isotope99Mo that crumbles into99mTc with a half-life of approximately 2.75 days. The99Her name is Moparentisotope and99mTc is her nameDaughterIsotope.
So the nuclear plant produces the mother isotope, which relatively slowly decays into the daughter isotope, and the daughter is chemically separated from the mother in the hospital/clinic. The chemical separation device is denoted as a in this example99mTc-Generator:
It consists of a ceramic column with99Moadsorbedon its upper surface. A solution called atElutionsmittelpassed through the column reacts chemically with all99mTc and arises in a chemical form suitable to be combined with a drug to produce a radiopharmaceutical. The arrangement shown in the figure on the right is denoted as apositive pressureSystem in which the eluent is pushed through the ceramic column by a pressure slightly above atmospheric pressure in the eluent bottle.
For reasons of radiation protection, the ceramic column and the collection vessels must be surrounded by a lead shield. Also, all components are manufactured and must be kept in a sterile condition since the collected solution will be administered to patients.
Finally oneIsotopenkalibratoris required if a99mTc generator is used to determine radioactivity for preparing patient doses and verify presence99Mo is present in the collected solution.
Operation of a 99m Tc generator[edit|edit source]
Suppose we have a sample of99Mo and assume that at the time
there are
Cores in our sample and nothing else. The number
von99Mo nuclei decrease with time according to the radioactive decay law as discussed inChapter 3:
Wo
is the decay constant for99Mo.
So the number of99Mo nuclei decaying in a small time interval
is given by
Since99Mo breaks down into99mTc, the same number of99mDuring this period, Tc nuclei are formed. At a time
, only a fraction
those cores will still be there99mTc also decays. The time for99mTc until decay is given by
. Plugging this into the radioactive decay law, we get:
Now let's summarize the small contributions. In other words, we integrate over
to find the number
, that is the number of all99mTc nuclei present at this time:
Finally we solve this integral and find:
The figure below illustrates the result of this calculation. The horizontal axis represents time (in days), while the vertical represents the number of cores present (in arbitrary units). The green curve illustrates the exponential decay of a pure sample99mtc The red curve shows the number99mTc nuclei present in a99mTc generator that is never eluted. Finally, the blue curve shows the situation for a99mTc generator eluted every 12 hours.
Photos taken in a hot nuclear medicine lab are shown below:
Externe Links[edit|edit source]
- Molybdenum Reserve Concerns- News from 2008 compiled by the British Nuclear Medicine Society.
- Zyklotron Java Applet- a Java-based interactive demonstration of the operation of a cyclotron by GFU-Kwun Hwang, Dept. of Physics, National Taiwan Normal University, Virtual Physics Laboratory.
- Nuclear Power Plant Demonstration- a Java-based interactive demonstration of the control of a nuclear reactor. Also includes atomic energy information links.
- ANSTO– Information on the Australian Nuclear Agency.
- Medicinal Valley- contains information on what nuclear medicine is, the production of nuclear pharmaceuticals, molybdenum and technetium - from the Dutch Energy Research Foundation Petten.
FAQs
What is the basic physics of nuclear medicine? ›
Nuclear medicine uses radioactive materials and their emitted radiation from the body to diagnose and treat disease. Unstable atoms (radionuclides) are typically administered orally or intravenously and, less commonly, intra-arterially, directly into the CSF spaces, peritoneum, or joint space.
How are radioisotopes produced in nuclear medicine? ›Isotopes used in medicine
Many radioisotopes are made in nuclear reactors, some in cyclotrons. Generally neutron-rich ones and those resulting from nuclear fission need to be made in reactors; neutron-depleted ones such as PET radionuclides are made in cyclotrons with energy ranging from 9 to 19 MeV.
What is Nuclear Physics? Nuclear physics is a scientific discipline that studies the structure of nuclei, their formation and stability. It mainly focuses on understanding the fundamental nuclear forces in nature and the complex interactions between neutrons and protons.
Is it hard to study nuclear physics? ›The science behind nuclear energy is incredibly complex and requires expert knowledge and training to safely extract power from the nuclei of atoms, usually from nuclear physicists.
Does nuclear medicine require math? ›Individuals interested in becoming a nuclear medicine technologist, should prepare for their future career by taking high school courses heavy in math and science like algebra, biology, chemistry, geometry, statistics, and physics.
What are 3 uses of radioisotopes? ›- Tracer Applications.
- Irradiation of Food and Mail.
- Smoke Detectors.
- Other Applications.
There are two uses of radioisotopes: they can be utilised as a source of radiation energy and as a diagnostic tracer.
Which radioisotopes are most commonly used in nuclear medicine procedures today? ›The radioisotope most widely used in medicine is technetium-99m, employed in some 80% of all nuclear medicine procedures. It is an isotope of the artificially-produced element technetium and it has almost ideal characteristics for a nuclear medicine scan.
Is there a lot of math in nuclear physics? ›Neutron transport, shielding work, nuclear criticality, and nuclear safety also involve a lot of math.
Can anyone study nuclear physics? ›The education needed to be a nuclear physicist is normally a bachelor's degree. Nuclear physicists usually study physics, nuclear engineering or biology. 53% of nuclear physicists hold a bachelor's degree and 37% hold a master's degree.
Do you need calculus for nuclear physics? ›
To prepare for a bachelor's in nuclear engineering program, high school students should take calculus during their junior or senior year, which typically requires taking geometry in ninth grade and algebra in middle school. Chemistry and physics are the most important fields in nuclear engineering.
Why should I study nuclear physics? ›Additional Links. Nuclear physics is an important pursuit because the study of the nucleus of the atom is at the heart of our ability to understand the universe. It provides answers and expands our knowledge of both the infinitely small and the extremely large.
What is the father of nuclear physics? ›Sir Ernest Rutherford, Lord of Nelson, died in October 1937. Forgive my too short account of his enormous history: he was the reference head of a community which is one of the most impressive in the history of science. Thus, the father of nuclear physics.
What is a nuclear scientist called? ›Physicist - Careers in Nuclear Medicine. Nuclear medicine physicists and engineers are experts in the interactions between ionizing radiation and matter, nuclear imaging instrumentation and radiation dosimetry. They typically also have expertise in image processing and computer science.
What is the most difficult degree in physics? ›Quantum mechanics is deemed the hardest part of physics.
What is the most difficult branch of physics? ›Atomic Physics is considered one of the hardest branches of Physics.
Do nuclear physicists make a lot of money? ›The average Nuclear Physicist salary is $128,140 as of March 28, 2023, but the salary range typically falls between $111,316 and $149,351. Salary ranges can vary widely depending on many important factors, including education, certifications, additional skills, the number of years you have spent in your profession.
What is the difference between radiology and nuclear medicine? ›What is the difference between nuclear medicine vs radiology? The primary difference between nuclear medicine and radiology is that nuclear medicine creates images using internal radiation waves from inside the body while radiology develops images through apply external energy waves to the body.
How many questions are on the nuclear medicine exam? ›The CBNC certification examination contains 160 questions and the recertification examination contains 100 questions. The CBNC examinations cover the following content areas.
What are the most radioisotopes used? ›The radioisotope most widely used in medicine is technetium-99m, employed in some 80% of all nuclear medical procedures. It is an isotope of the artificially-produced element technetium and has almost ideal characteristics for a nuclear medical scan.
What radioisotopes are commonly used in everyday life? ›
| Radioisotope | Half-life | Use |
|---|---|---|
| Gallium-67 | 78.28 hours | Used in imaging to detect tumours and infections. |
| Iodine-123 | 13.22 hours | Used in imaging to monitor thyroid function and detect adrenal dysfunction. |
| Thallium-201 | 73.01 hours | Used in imaging to detect the location of the damaged heart muscle. |
What is it used for? Because Sr-90 generates heat as it decays, it is used as a power source for space vehicles, remote weather stations, and navigational beacons. It also is used in industrial gauges and medically, in a controlled manner, to treat bone tumors.
What type of radiation is typically exploited in most nuclear medicine procedures? ›Two common uses of nuclear medicine for treatment include radioactive iodine therapy and brachytherapy (a form of radiation treatment where a sealed radiation source is placed inside or next to the area requiring treatment).
What are the dangers of radioisotopes in medicine? ›effects: hair loss, skin burns, nausea, gastrointestinal distress, or death (Acute Radiation Syndrome). Long-term health risks include an increased cancer risk. Such risks depend upon the function of the specific radioisotope; and the route, magnitude, and duration of exposure.
What are 4 applications of radioisotopes? ›The application of radioisotopes in tracing, radiography, food preservation and sterilization, eradication of insects and pests, medical diagnosis and therapy, and new variety of crops in agricultural field is briefly described.
What is the most common radiotracer in nuclear medicine? ›The most common radiotracer is F-18 fluorodeoxyglucose (FDG). It is just one of many radiotracers in use or in development. FDG is a compound similar to glucose, or sugar. Highly active cancer cells need more energy than normal cells.
Which of the radioisotope is used heavily in nuclear medicine? ›Technetium-99m (γ, 90%, half-life 6.02 h) has for several decades been the radioisotope used in the largest number of clinical radionuclide scans, and the invention of the 99mTc generator, enabling daily availability of radiopharmaceuticals in all major hospitals, was one of the key steps in the evolution of nuclear ...
What is the most common imaging device used in nuclear medicine? ›Specially designed cameras allow doctors to track the path of these radioactive tracers. Single Photon Emission Computed Tomography or SPECT and Positron Emission Tomography or PET scans are the two most common imaging modalities in nuclear medicine.
Is nuclear physics a good career? ›Yes, nuclear physicist jobs are in demand. The job market for analysts is projected to grow 9% from 2018 to 2028.
What's the difference between a nuclear physicist and a nuclear engineer? ›Nuclear physics focuses on studying nuclear particles and their development of theories, while nuclear engineering focuses on using the ideas of atomic physics. In nuclear physics, jobs are more viable for people holding a master's and a doctorate than in nuclear engineering, which absorbs a bachelor's student.
How long is a nuclear physics course? ›
Over two years, you will study the fundamentals and applications of nuclear science, including materials analysis, dating techniques, nuclear medicine, and nuclear energy. The degree is a mix of coursework and projects, comprising individual and group-based research.
Do you need a PhD to be a nuclear physicist? ›The position of a nuclear physicist requires a master's degree in nuclear science or physics, and many have a master's degree in both, which each require written theses and thirty to sixty-six additional class hours. Many nuclear physicists also have a doctorate degree.
Where can I study nuclear physics online? ›Learn about Nuclear Physics
You can study the profound nature of particles such as these with courses on the edX.org platform. edX hosts courses created in partnership with leaders in the field of applied and theoretical nuclear physics.
Prior to becoming a nuclear medicine physicist, one usually undergoes general training as a medical physicist. Nuclear medicine physicists have a master's or doctorate degree in one of the following fields: Physics. Medical Physics.
What is a nuclear engineer salary? › How many years does it take to become a nuclear engineer? ›How Long Does it Take to Complete a Nuclear Engineering Program? The Bachelor of Science degree in Nuclear Science and Engineering is a basic four-year course, but a specialized five-year course can incorporate a master's degree.
What math is used most in physics? ›- Algebra. Algebra is a foundational study for most advanced forms of mathematics. ...
- Calculus. ...
- Geometry. ...
- Statistics. ...
- Trigonometry. ...
- Try direct mathematical study. ...
- Write it out. ...
- Check your work.
- Multivariate calculus.
- Ordinary differential equations.
- Partial differential equations.
- Linear algebra.
- Group theory.
- Real analysis.
- Complex analysis.
- Calculus of variations along with Lagrangian and Hamiltonian mechanics.
Nuclear physics is ubiquitous in our lives: Detecting smoke in our homes, testing for and treating cancer, and monitoring cargo for contraband are just some of the ways that nuclear physics and the techniques it has spawned make a difference in our safety, health, and security.
What are real life examples of nuclear physics? ›Most may not realize that discoveries in nuclear physics are the basis of life-saving technologies such as radiotherapy, cancer research, medical imaging, and smoke detectors. Nuclear technologies keep us safe by their use in export-control tracking of radioactive and dangerous materials across our borders.
Who is a famous nuclear physicist? ›
Enrico Fermi (1901-1954) was an Italian physicist and recipient of the 1938 Nobel Prize in Physics. In 1942, Fermi relocated to the Chicago Met Lab, where he built an experimental reactor pile under Stagg Field at the University of Chicago.
Which country split the atom first? ›It was a British and Irish physicist, John Cockcroft and Ernest Walton, respectively, who first split the atom to confirm Einstein's theory.
Who is famous for nuclear physics? ›E. Rutherford is regarded as the father of nuclear physics.
Is nuclear physics difficult? ›The science behind nuclear energy is incredibly complex and requires expert knowledge and training to safely extract power from the nuclei of atoms, usually from nuclear physicists.
What are three careers in nuclear science? ›Nuclear technician, nuclear engineer, and medical physicist are just three of the possible careers for those trained in nuclear science. Nuclear technicians are assistants to those who perform research on nuclear science, such as engineers, physicists, and more.
What is the salary of nuclear scientist in America? ›$65,500 is the 25th percentile. Salaries below this are outliers. $121,500 is the 75th percentile.
What are the three elements of nuclear medicine? ›Nuclear medicine is described by three elements - clinical problem, the radiopharmaceutical and the instrumentation. Since nuclear medicine involves exposure of patients, the general principles of radiation protection should be applied.
What are the three main classes of techniques used in nuclear medicine? ›A nuclear medicine scan consists of 3 phases: tracer (radionuclide) administration, taking images, and image interpretation.
What are the major nuclear physics? ›Nuclear physicists usually study physics, nuclear engineering or biology. 53% of nuclear physicists hold a bachelor's degree and 37% hold a master's degree.
How does nuclear radiation work physics? ›Nuclear radiation (also called ionising radiation) is energy released as high-speed charged particles or electromagnetic waves. Radiation can come from many sources, both natural and manufactured.
What are the 3 C's of nuclear safety? ›
Requirements: Accountabilities: As Nuclear Professionals, everyone shall demonstrate respect for nuclear safety and security by: Knowing how your work impacts on Control the power, Cool the fuel and Contain radioactivity (3C's).
Who is the father of nuclear medicine? ›Georg Charles de Hevesy: the father of nuclear medicine.
What is the most commonly used nuclear medicine? ›Two common uses of nuclear medicine for treatment include radioactive iodine therapy and brachytherapy (a form of radiation treatment where a sealed radiation source is placed inside or next to the area requiring treatment).
What diseases can nuclear medicine detect? ›Doctors use nuclear medicine tests to diagnose, evaluate, and treat various diseases. These include cancer, heart disease, gastrointestinal, endocrine, or neurological disorders. Nuclear medicine determines how the body is functioning at a cellular level.
What is the difference between nuclear medicine and nuclear radiology? ›The main difference between nuclear medicine imaging and other radiologic tests is that nuclear medicine imaging evaluates how organs function, whereas other imaging methods assess anatomy (how the organs look).
Is nuclear medicine same as MRI? ›MRI uses a strong magnetic field and radio waves to produce high-quality, detailed images of internal body structures. This is a form of non-ionizing radiation. Nuclear medicine uses an ionizing radioactive tracer, usually injected into the blood, to produce images that show function of internal organs.
What is an example of nuclear physics in real life? ›Most may not realize that discoveries in nuclear physics are the basis of life-saving technologies such as radiotherapy, cancer research, medical imaging, and smoke detectors. Nuclear technologies keep us safe by their use in export-control tracking of radioactive and dangerous materials across our borders.
Is nuclear and radioactive the same? ›Nuclear incidents involve detonation of a nuclear device whereas radiological incidents produce radiation without detonation of a nuclear device.
What is the difference between radiation and radioactivity? ›What is the difference between radioactivity and radiation? Radiation is the energy or particles that are released during radioactive decay. The radioactivity of a material refers to the rate at which it emits radiation.